Angels are certainly real; created by God as spiritual beings. They are a "company", not a race. We are the human race. We are all, through Adam, propagated.

Can demons indwell people? Yes. Christians? No. Is there any test given where we can know some one is possessed? No. Is there anywhere in scripture that we are given instructions in how to exorcise demons? No.

Rev 4:6 Same as in Ezekiel -

Our Position
Psalm 8:
The theme is the greatness of God
Verse 5 -- man was made a little lower than God given dominion over creation and parallels the creation account.

Lucifer/Satan
Isaiah 14:12 Ezek 28 (the great cherub)
For Satan and the fallen angels there is no redemption there is no option of salvation available for them.
For the holy angels there is no need for redemption.
2Cor 2:11; Eph 6:11,12; Eph 2:2; John 14:30; 2Cor 4:4; 1John 2 (world system); 1Pet 5:8 (is powerful); 1John 4:4 because greater is he that is in you, than he that is in the world.

Gabriel
Daniel 8:16 9:21
Luke 1:19, 26
Stands in the presence of God

Michael (the General)
Daniel 10:13, 21
Angels are categorized in ranks.
Jude 9; Rev 12:7;

Satan - reminder of sin in the world
Gabriel - reminder of salvation
Michael - the spiritual battle we are in